Tunnel No. 1 exit (Photo courtesy of Sichuan Provincial Department of Transportation)

On May 7, the No. 1 tunnel of Laoyingpan of Xizhao Expressway was completed. So far, after 1,155 days of construction, the three tunnels of the Laoyingpan tunnel group have been broken through, and another control project of the Zhao Expressway has been overcome.

The Xizhao Expressway invested and constructed by China Railway and China Railway Urban Investment Group connects Zhaotong City, Yunnan Province and Xichang City, Liangshan Yi Autonomous Prefecture, Sichuan Province, with a total length of 184.8 kilometers, including 16.7 kilometers and 168.1 kilometers of new high-speed along the Yangtze River, and the whole line adopts the standard construction of four-lane expressway with a design speed of 80 km/h.

Tunnel construction site (courtesy of Sichuan Provincial Department of Transportation)

Xizhao Expressway Laoyingpan tunnel group is located in the alpine valley area of Jinyang County, Liangshan Prefecture, the tunnel group design longitudinal slope of 25‰, the minimum curve radius of 970 meters, the straight line distance between the import and export is only 1.6 kilometers, but the height difference reaches 213 meters, in order to solve the problem of climbing the mountain line, the second hospital of China Railway adopts the spiral climbing method to realize the design idea of "exchanging length for height".

It is reported that under the construction of the Laoyingpan spiral tunnel group, the 1.05-kilometer-long No. 2 tunnel and the 1.24-kilometer-long No. 3 tunnel have been broken through on April 7, 2024 and December 30, 2023 respectively. The No. 1 tunnel is 5.1 kilometers long. (ENDS)